The present invention relates in general to temperature control systems, and in particular to a temperature control system that integrates magnetic sensitive elements and infrared sensor on a single chip for a reliable and cost effective implementation.
There are a variety of consumer goods that require a temperature control mechanism. For these types of goods, a control knob typically adjusts the target temperature within a given range as determined by the application. In an electric iron, for example, the temperature of the sole plate is controlled and adjusted to a setting determined by the characteristics of the material to be ironed. The electric iron must therefore have the capability to detect the user's requested temperature, measure and control the temperature produced by the iron.
To detect the position of a temperature control knob, existing devices typically use a potentiometer whose resistance value changes as the knob is rotated. Thus, by measuring the resistance value of the potentiometer, the device detects the setting of the control knob. While this implementation is relatively cost effective, it has the disadvantage of relying on a physical contact between the fixed resistance element and the wiping element. In an environment where the temperature is very high by the nature of the application, good reliability and accuracy is difficult to achieve at an acceptable cost. Another method for temperature control uses a bimetallic strip element in close proximity to the heated parts of the structure. Cost and reliability, however, remain difficult requirement to meet with this type of implementation as well. In the consumer market, the selling price of such products is of paramount importance, and therefore the cost of manufacturing becomes a significant factor.
There is therefore a need for a low cost and robust temperature sensing and control system that is suitable for the consumer market.